Educational apparatus



y 23, 1940- o. M. GLUNT 2,209,157

EDUCATIONAL APPARATUS Filed June 2, 1959 REPRODUCE RECORD RECORD REPRODUCE INVENTOR 0. M. GLUNT A T TORNE V Patented July 23, 1940 UNITEDSTATES PATENT OFFICE Bell Telephone Laboratories,

Incorporated,

New York, N. Y., a corporation of New York Application June 2, 1939,Serial No. 276,980

3 Claims.

This invention relates to apparatus for use in educational work andparticularly to a simple inexpensive but efiicient sound recording andreproducing mechanism for use in teaching by 5 sound.

In certain types of educational work such as music and languages whichare best learned by imitation of a standard it is very desirable to havea recorded standard of sound as well as a recording and reproducingmeans with which the pupil may make repeated recordings andreproductions for purposes of comparison with the standard sound.

The present day magnetic tape recording methods and apparatus, becauseof the high quality now attainable and the ease and simplicity withwhich the recording and reproducing operations using this material maybe performed, lend themselves admirably to the educational field.

In order to supply this field with apparatus that will meet all of therequirements and will easily be within a price field to make itavailable to the most users it is proposed by this invention toconstruct a recording and reproducing machine comprising two endlessmagnetic tapes driven synchronously one to contain a recording of thestandard, the other constituting the medium upon which the pupil canalternately reccord and observe his efforts in comparison with thestandard sound. Conventional recording and reproducing magnets may beprovided in connection with each tape with simple switching means forselectively connecting sound recordingreproducing mechanism with eithertape for either recording or reproducing.

It is important that both tapes be driven at exactly the same speed inorder that there may be no variations in pitch and for this reason theyare preferably mounted to travel in parallelarelation over the same pairof drums or reels.

In the drawing, Fig. l is a view of an apparatus assembly embodying thefeatures of the invention and Fig. 2 is a circuit schematic of theswitching connections.

As shown in Fig. 1, 5 and 6 designate a pair of drums rotatably mountedupon vertical supporting brackets l and 8 supported near opposite endsof a hollow metal base 9.

Threaded over the drums 5 and 6 are two endless magnetic tapes H1 and IIadapted to cooperate with recording and reproducing heads i2 and I3,respectively mounted upon horizontal plates l4 and I5 supported upon thevertical brackets I and 8.

The recording and reproducing heads are stationary on their mountingsand in order that the entire length of the endless magnetic tapes I 0and Il may be passed through these heads without putting an injuriousstrain upon the tapes and still provide for storage space for severalspirals of the tapes disposed axially of the drums each of the tapes isstored on the drums with the spirals in an interlaced relation such thatonehalf of the length forms a first spiral in one direction axially ofthe drums 5 and 6 and the remainder of the tape forms a return spiralintermediate the turns of the first spiral. With the tapes I0 and Hdisposed in this manner on the drums 5 and 6, it will be apparent as thedrums rotate that any given point in either tape will complete acomplete axial cycle of travel on the drums in a complete cycle oflongitudinal movement and each active section of tape will be passedthrough its corresponding recording-reproducing head in substantially astraight line movement from one drum to the other. This feature isdisclosed and claimed in a copending application to C. C. Towne, SerialNo. 284,155, filed July 13, 1939.

Mounted within a well 2| provided in the metal base 9 is a synchronousdriving motor 22 connected by pulleys and belts 23 and 24 with the drum5. The numerals 25, 26. 21 and 28 designate elements of the amplifierequipment mounted upon the base 9.

As shown in the wiring diagram Fig. 2, the switching equipment requiredto perform the functions of the recording reproductions necessary tocarry out the purpose of the invention comprises two eight-pole doublethrow switches 30 and 3| that are interconnected with a microphone 32and a telephone receiver 33 preferably of the loud-speaker type in sucha manner that the microphone 32 and the receiver 33 may beinterchangeably connected with the two recording and reproducing headsl2 and I3.

In the operation 0 the system it will be assumed that the upperrecorder-reproducer head I2 is the one used by the instructor to producethe sound pattern to be followed while the lower recorder-reproducer I3is the medium to be used by the pupil.

In the normal operation of the equipment the closure of the switch 30into its lower position will connect the microphone pick-up 32 throughamplifier 36 to the recording-reproducing windings of head l2 so thatthe tape III will receive the voice currents from the microphone 32representing the instructors lesson. The reversal of the switch 30 intoits lower position disconnects the microphone 32 from the input of theamplifier and connects the recording-reproducing head l2 therewith inreproducing position and will connect the output end of the amplifier 36with the loud-speaking telephone 33 so that the pupil may listen to thematterrecorded upon the tape i0.

- With the switch 30 in its open or neutral position and the switch 3|in its upper position of operation the microphone 35 will be connectedinto recording relation with the recording-reproduci'ng head i3 throughthe amplifier 36 so that the pupil may record on the tape II.

By moving the switch 3! into its lower position the recorder-reproducerhead i3 is connected to the loud-speaker 33 which will permit the pupilto listen to the reproduction of his own recording. By propermanipulation of the switches the pupil can so time his recording and thereproductions of his and the instructor's recordings that the entirerecording or any particular portions of it may be brought into thereceiver in any timed sequence that he desires.

In the recording positionsof the switches 30 and 3i polarizing anddepolarizing magnets 40 and H are brought into the circuit to erasepreviously recorded matter and prepare the tape for subsequentrecordings.

What is claimed is:

1. An educational apparatus for teaching by sound comprising a magnetictape upon which is recorded a standard sound, asecond magnetic tapeadapted to receive a pupil's imitation of the standard sound, recordingmeans cooperating withthe second tape, reproducing means selectivelyconnectable to each of the tapes and means for driving the two tapes insynchronism.

2. An educational apparatus for teaching by sound comprising a magnetictape upon which is recorded a standard sound, a second magnetictapeadapted to receive a pupil's imitation of the standard sound, recordingmeans controlled by the pupil and connectable with the second tape,reproducing means controlled by the pupil and selectively connectablewith both tapes and a pair of drums over which both tapes are carried inparallel.

3. An educational apparatus for teaching by sound comprising a magnetictape upon which is recorded a standard sound, a second magnetic tape,recording means controllable by the pupil and connectable with thesecond tape, reproducing means controlled by the pupil and selectivelyconnectable with each of the tapes and means driving the two tapessynchronously comprising a pair of drums over which the two tapes arecarried in parallel.

OMER M. GLUNT.

